I just did a 23 mile, 9.5 hours, run/walk/crawl/roll the other week. I brought along these drops, which have oxygen, minerals, and enzymes in them, called Cell Food, and they were amazing! They kept my energy up! And I could feel the results almost instantly. I took way more than the recommended dosage, of course, because of my level of activity. So just thought I'd share.
http://www.amazon.com/Cellfood-Liqu...46188492&sr=8-2&keywords=mineral+drops+oxygen
http://www.amazon.com/Cellfood-Liqu...46188492&sr=8-2&keywords=mineral+drops+oxygen